Spark plug



Dec. 28 r1926. 1,612,091

P. BERNAL f SPARK PLUG Filed Feb. 1925' lNVENTOR ATTORNEYS Pedro ernal,

WZ ,ag

kPatented Dc. 28, 1926.

UNITED STATES PEDRO BERNAL, oF HoNoLULU, TERRITORY or HAWAII.

SPARK rLuG. A

Application led February 6, 1925. Serial No. 7.387.

This invention relates to improvements in spark plugs.

An object of the invention is to provide a spark plug having renewable electrodes.

It is also an object of the invention that the improved spark plug be constructed to prevent accumulation of carbon.

It is also an important object of thevinvention that the improved spark plug be sturdy7 in construction, easy to assemble or dissemble when renewing the electrodes, and inexpensive to manufacture.

The invention is illustrated by way of example in the accompanying rawings, in which:

nFigure 1 is a perspective view of the spark plug,

Figure 2 the same,

Figure 3 is a sectional view Vtaken substantlally on line 3-3 of Figure 2, and,

Figure 4 is a oup view showing in perspective the insu atedgelectrode and its associatedconductor elements. Referring to the drawings more particularly, 10 indicates a spark plug shell, 11 the insulator element of the spark plug, and 12 the usual threaded bushin for securing the insulator element 11 within the shell 10.

The lower end bore portion 13 of the shell 10 is of less Idiameter than the bore portion is a vertical sectional view of 14 thereby providing a. shoulder 15. The

insulator element 11 fits tightly within the bore portion 13. The insulator 11 is rovided with an-annular enlargement 16 w ich seats upon the shoulder 15, and a packing washer 17 is inte between the enlargement' 16 and shoulder 15. The shell 10 has its lower end portion provided with a bore 17 adapted to receive the electrode 18. The 'electrode 18. is in the form of an elongated pm termmating at one end in a head 19 which is preferably I driver slot 20.A It wi "be noted the head 19 is beneath the washer 17 `and the electrode 18 is rigidly held against movement byv the bushing 12, said bushin bein threaded into the 'bore portion 14 ofgthe's ell as shown. Preferably, a washer 21 is interposed between the bushing 12 and enlargement 16 of the insulator element.

The insulator element end formed with a central longitudinal bore which accommodates the electrode 22. The bore accommodating electrode 22 is enlarged at its upper end as at 23, and into this enf'rovided with a.; screw 11 has its upper' adapted to receive the electrode 22` and saidbore terminates at its outer end in an en'- largement 26 which is threaded as sl1own` and adapted to receive the ythreaded portion 27 of a bndin post 28. The post 28 has a reduced threa ed portion 29 which carries a binding nut 30.

It will be noted that the electrode 22 is similar in structure to the electrode 18 viz; it terminates at its one end in a head 31 which is provided with a screw driver slot. Preferably the head 31 is counter-sunk in the insulator element 11 as shown. The.

head 19 of electrode 18 is also counter-sunk in the shell 10, Figure 2.

Between the head 31 of electrode 22 and post 2 8 thereis interposed a plate 32 to insure good contact between the electrode andv the post. N

It is important to observe thatthe electrodes 18 and 22 extend av considerable distance below the shell and thus providin a considerable length of said electrodes tween which sparks can occur. Also by permitting the electrodes to de nd a considerable distance below the she l and main'- taining the same straight vas shown,v minimizes the accumulation of carbon upon the electrodes in an obvious manner.

If it is desired to renew either of the electrodes 18 or 22, the same can be accomplished in a short interval of time. The manner in which the electrodes can be relmoved and replaced is thought to be entirely obvious and therefore a detail description thereof would seem unnecessary.- It might be noted that before attempting to withdraw either of the electrodes, a screw driver m1 ht be used to loosen the same.

hile I have shown and described the preferred form of my invention, Iwish it to be understood that I am aware of the fact that the generalf'c'onstruction, combination cated by the appended claims.

1 claimtl. In a spark plug' construction an'insulater clement, a metallic extension, Iixed in the outer end thereof, an elongated pinlike electrode extending centrally' and longitudinally through the insulator element and metallic extension said electrode being freely removable and said metallic extens1on having a bore enlargmnent at 4itsl outer end, a head formed upon the outer end of the pin elertrode and disposed in said bore enlargement, and a metallic terminal post threaded into the bore enlargement of said metallic extension and seating the head of said pinlike electrode.

2. In a spark plug construction an insulator element, a metallic extension, fixed. in

the outer end thereof, an elongated pin-like electrode extending centrally and longitudinally through the insulator element and Ine- 2h tallic extension, said electrode being freely removable and said metallic extension having,` a bore enlargement at its outer end, a head having a screw driver slot formed upon the outer end of the pin electrode and 25 and a'metallic plate interposed between the 3U head ofsaid electrode and associated end of terminal post.

PEDRO BERNAL. 

